Introduction:Heart disease (HD) exerts high morbidity and mortality in Brazil. Screening echocardiography (echo) may be a useful tool in the primary care (PC) setting. We aimed to evaluate the reasons for disagreement between screening echo, acquired by non-experts, and standard echo in the Brazilian PC system.Methods:Over 20 months, 22 healthcare workers at 20 PC centers were trained on simplified handheld (GE VSCAN) echo protocols. Screening groups, consisting of patients aged 17-20, 35-40 and 60-65 years, and patients referred for clinical indications underwent focused echo. Studies were interpreted in US and Brazil by telemedicine, and those diagnosed with major or severe HD were referred for standard echo performed by an expert. Major HD was defined as moderate to severe valve disease, ventricular dysfunction/hypertrophy, pericardial effusion or wall-motion abnormalities. A random sample of exams was selected for evaluation of variables accounting for disagreement.Results:From 2237 patients screened, a sample of 768 was analyzed, 651 (85%) from the referred group. Mean age was 58?15 years, 62.5% were women; 68.4% had hypertension and 23% diabetes. Quality issues were reported in 5.8%, and the random Kappa for major and severe HD between screening and standard echo was 0.51 and 0.45. The most frequent reasons for disagreement in screening were: overestimation of mitral regurgitation (MR) (17.9%, N=138), left ventricular (LV) dysfunction (15.7%, N=121), aortic regurgitation (AR) (15.2%, N=117), LV hypertrophy (13.5%, N=104) and tricuspid regurgitation (12.7%, N=98). Misdiagnosis of morphological abnormalities of the aortic and mitral valves were observed in 12.4% and 3.0% of the cases. Underestimation of AR and MR occurred in 4.6% and 11.1%. Of note, among 257 patients with initial diagnosis of mild/moderate MR, 129 (50.2%) were reclassified to normal, as well as 101 (80.8%) among 125 initially flagged with mild/moderate LV dysfunction.Conclusion:Although screening echo with task-shifting in PC may be a promising tool in low-income areas, estimation of valve regurgitation and LV function and size account for considerable disagreement with standard exams. Training and quality-assurance strategies must be implemented to improve accuracy.